on."

"I think so, too," replied Tom.

"What?" asked Jim.

"Take more 'rations' with us," replied Tom.

"Wake up, boy," cried Jo, giving him a shove and toppling him over on
deck. "You think so much about rations that you are getting irrational."

"That gives me an idea," began Juarez, when Jo and Tom had been
separated and quiet restored.

"An idea of war?" asked Berwick.

"No," laughed Juarez. "But would it not be a good thing to go on shore
and camp there until we had made a complete exploration of the place?"

"Just the thing!" cried Jo and Tom.

"I am afraid it is hardly wise," demurred the professor.

"Ugh!" sniffed Tom. "I guess we can take care of ourselves."

"Besides, there isn't anyone on the island," added Jo.

"Better not act on that assumption," advised the professor.

"I don't know but what it would be a good plan," said Jim. "We would be
able to get over it more quickly if we didn't have come back to the boat
every night."

"There is something in that," admitted the professor, "though as far as
I can see this doesn't look like the portion of the island shown on the
chart."

"No," admitted Jim, "but this may be the opposite end of the island."

"That is true, too. Suppose we go down into the cabin and have another
look at it?"

"Do you think it will be safe?" asked Berwick.

"Safe? Why not?"

"You know what happened to the other one," laughed the engineer.

"It probably slipped off the string," replied the professor, "and
dropped down into the bilge. Anyway we appoint you watchman to see if
anyone is spying about."

"All right," agreed Berwick, "but I've got a kind of feeling that that
little devil of a Mexican ain't far away."

"Booh!" broke in Tom. "Didn't we see him go up into the air with the
lugger?"

"Maybe we did," admitted Berwick gloomily, "but I don't believe fire
would ever hurt him."

"I don't believe he is fire proof," declared Tom. "And even if he is
that isn't any reason why we shouldn't have a look at the map."

It was some time after supper before the matter was again alluded to,
then they all went below to further study the chart.

Taking the precious paper from his pocket and spreading it out on the
table, Jim and the professor analyzed carefully the various marks and
drawings.

"We have got pretty well fixed in mind now the shape and landmarks of
the island," said Jim, when they had studied the document carefully. He
then folded up the chart, putting